U.S. Pat. No. 4,980,844 discloses a method and apparatus for diagnosing the mechanical condition of a machine. The method includes the following steps: sensing reference vibrational characteristics of a machine in the time domain; creating a reference signature from the reference vibrational characteristics; saving the reference signature; sensing test vibrational characteristics of the same machine in the time domain; creating a test signature from the test vibrational characteristics; automatically computing a measured distance between at least one point of the reference signature and at least one corresponding point on the test signature; automatically comparing the measured distance against a threshold value to determine if the machine is operating normally or abnormally; and providing a signal when the comparison indicates abnormal operation.
U.S. Pat. No. 5,804,726 discloses a device for testing mechanical devices using acoustic signature analysis of the sonic signature of such devices by filtering out the frequencies of interest, recreating such frequencies from their respective harmonics, and then correlating the recreated frequencies to pre-determined known characteristics or parameters developed from valid devices to predict the long term operability of other unknown devices in a noisy environment like a factory or an airport wherein other sources of sound and/or vibration are present.
U.S. Pat. No. 6,370,957 discloses a method for determining the operational condition of a rotary machine. The method comprises the steps of monitoring the machine under a baseline operating condition and collecting baseline vibrational data. A preselected number of baseline parameters are calculated from the baseline vibrational data. Next, a first baseline operational indicator is calculated from the baseline parameters, and the baseline parameters and the first baseline operational indicator are stored in a memory location. The machine is then monitored under a subsequent operating condition, and subsequent vibrational data is collected during the subsequent operating condition. A preselected number of subsequent operating parameters is calculated from the subsequent vibrational data, and a first subsequent operational indicator is calculated from the preselected number of subsequent operating parameters. Finally, the baseline data is compared to the subsequent operating data to determine the condition of the machine.
U.S. Pat. No. 6,694,285 discloses a monitoring method and device which is capable of determining the overall fitness or condition of the device being monitored while simultaneously detecting unknown or unrecognized vibration frequencies. In addition, setting threshold values corresponding to the environment surrounding the device reduces the incidence of false alarms. False alarms may be controlled while detection of true alarms may be maximized by assigning values indicative of thresholds crossed and averaging the values before issuing an alarm. The monitoring system may also provide detailed information as to the operating condition of the device so as to allow the device to operate closer to its margin of safety. Thus, the device may handle more power or speed, without the need to modify the physical design. In addition, an onboard processing unit may be used to determine when the physical load on the device is approaching its physical limits and warn the operator so as to prevent the device from exceeding those limits.
U.S. Pat. No. 6,915,235 discloses a method for processing information related to an operational condition of a machine in a process plant, where the generated information is in a first data format. The information may be generated based on data in a second format. The second format may, for example, correspond to a format used by a certain type or types of process entities, whereas the first format may, for example, correspond to a format used to process operational condition information of other types of process entities in the process plant. Providing operational condition data for various types of process entities in a common format may, for example, assist an operator in ascertaining the relative importance of the operational condition for various types of entities.
U.S. Pat. No. 7,059,191 discloses a method for determining whether a device is defective by analyzing the sound signals generated by the device. Digital samples are generated to represent the sound signals. Digital samples are transformed from the time domain to the frequency domain to generate a frequency spectrum. By comparing the levels of intensity at a corresponding frequency to the threshold levels of intensity, defective devices can be determined.
U.S. Pat. No. 7,225,109 discloses a method and apparatus for detecting mechanical problems in machinery used in a process. A model of the process is developed using a modeling technique such as advanced pattern recognition and the model is used to generate predicted values for a predetermined number of the operating parameters of the process and vibration parameters of the machinery. Statistical process control methods are used to determine if the difference between the predicted and actual measured values for one or more of the parameters exceeds a configured statistical limit. A rule set is used to indicate an actual or probable fault in the machinery.
U.S. Pat. No. 9,097,595 discloses a system for determining the source of vibration of a nipped roll assembly including: a first substantially cylindrical roll; a mating structure positioned relative to the first roll to form a nip therewith; a plurality of annular nip condition sensor units mounted on the first roll; each of the annular nip condition sensor units being positioned at different axial locations along the first roll and configured to provide nip condition signals from the nip, the signals indicating a nip condition at multiple circumferential locations; and a processor associated with the sensor units that receives signals from the sensor units. The processor is configured to convert the signals from the sensor units into nip condition readings for the multiple circumferential locations at each axial location. Such a system can detect irregularities in a roll or the mating structure that can cause undesired vibration.
U.S. Patent Application Publication No. 2012/0296458 discloses various embodiments that enable audio data, such as music data, to be captured, by a device, from a background environment and processed to formulate a query that can then be transmitted to a content recognition service. In one or more embodiments, the audio data is captured prior to receiving user input associated with audio data capture, e.g., launch of an application associated with the content recognition service, provision of user input proactively indicating that audio data capture is desired, and the like. Responsive to transmitting the query, displayable information associated with the audio data is returned by the content recognition service and can be consumed by the device.